This is how accidents happen

Lack of proper safety and operation training is the cause of a large percentage of accidents.

Never use your cheek to hold a rifle steady.
Make sure no part is front of your nose.(Could be an optical illusion in the photo though but still.)
Make sure butt is squared up with your shoulder.

Look closer at his cheek and the butt isn't square with his shoulder. Too much of a gap at the top of the butt.

Owning a gun is like owning clothes or car. A gun has to fit a person properly(clothes) and be something they can handle(Lambogini vs. Prius for example). Sure the Arnold Swartzenegger or Sylvester Stallone type gun found in their movies looks cool but in reality most people including the actors wouldn't be able to safely fire them without something gong wrong.

I literally have no idea what you are talking about. I buy guns on a whim all the time and know how to handle them. I have guns from modern to WW1. Sure I like to stick to my Beretta, Python, and AR because that is what I have the most practice with and own about a dozen more. But I have been handed high power sniper rifles, full auto 9mm conversions, pre 1898 relics etc and had no problem. The safety is always the same and weapons handling skills are mostly transferrable from gun to gun.

Basically, you know how to use a gun or don't. It's has nothing to do with what type.